Transit concrete mixer



Sept. 1, 1931. c. M. TUCK TRANSIT CONCRETE MIXER Original Filed Jan. z, 1927 2 Sheets-Sheet H mm gmnntoz Sept. 1,1931. c, T c 4 1,820,954

' TRAQJSIT CONCRETE MIXER r I "I I OrigipaL'F'iled Jan 'ZG, 1927 ZShOOtS-SX'IOI 2 Patented Sept. 1,1931

nirso STATES CLARENCE M. TUcx', or SEATTLE, 'WAASHINGVTOLVI, AssIeNoa T MORRIS & BooGnER, V INCL, or sEAzr'rrE, WAVSIIZENGTON, A coarone'rroiv PATENT OFFICE TRANSIT" CONCRETE MIXER Application filed January 26, 1927, Serial No. 163,660. Renewed January 23,1931.

My invention relates to the art of transit concrete mixers. More particularly my invention relates to a concrete mixer mounted on an automobile truck, in which the mixer drum is fixedly mounted upon said truck.

In the concrete construction work, a large part of the expense arises by reason of the transporting of the materials, and by reason of thehandling of the materials incident to pig loading the same into the truck and depositing the same'upon the ground, and then lifting the same into mixers.

A primaryobject of myinvention is to provide 'atransit concrete mixer which will sc -vetotransport the material. from the pointwhere the said materials are'constituted into bat'ches, i.;e., where thecement, sand, and the crushed rock or gravel are supplied to the truck, andthen be capable so of receiving water at the pointof construction and thoroughly mixing the water, gravconcrete [mixersas heretofore provided,

el, sand and cement by means of. the power plantof the automobile, and then cause the elimination," of said mixed concrete from the drum without tilting the drumitself. A serious objection obtains to transmit which have the drum pivotally mounted so that it can be hoisted, as respects one end, as the method of dumping material from the ground. With the addition of the water, the ;weight becomes very great and, ac-

' terial.

the power plant of the automobile to the drum, to impart a rotary motion thereto for the purposeof mixing the contents.

in dotted line.

A further primary object of my invention is to providea transit concrete mixer having the drum vfixedly mounted thereon, which is characterized by an improved mixing means which impartsa circulation in a longitudinal direction of the drum, i. 0., back and forth throughout the length of the drum, which most thoroughly and elliciently mixes the contents-gravel, cement, sand and water.

, A condition which obtains in mixing the elements, which go to make up concrete in a drum, is that considerably more power is required initially than after. the water is distributed throughout the contents.

Another object of my invention is to provide a concrete mixer that embodies two sets of mixing blades, one set of which is disposed in a region adjacent theaxis of the mixing drum and being'arranged at a given'angle to the radius of revolution of the shaft on which it is mounted, and the In general, a'primary object of my invention is to overcome the various difiiculties above set forth, and to provide a transit concrete mixer which is characterized by its efficiency and economy of construction.

The above general objects of my invention, together with others inherent in the same, are obtained by the device illustrated in the following drawings, the same being preferred exemplary forms of embodiment of my invention, throughout which drawings like reference numerals indicate like parts.

Figure 1 is a view in side elevation of a transit concrete mixer embodying my invention, withthe internal portion thereof shown Figure 2 is a fragmentary view in side elevation of the drum and said internal mixing parts. 7

i saidshaftt Figure 3 is a view in end elevation of the .drum part of my invention. I

Figure 4 is an enlarged view of a detail of the same.

Upon the chassis 5 of an automobile 6, a

I concrete mixing drum 7 is fixedly mounted.

Axially disposed in this drum is shaft 8. Upon this shaft a sprocket wheel 9' is keyed. On driving the shaft 10 of the automobile,

- asprocket wheel 11 is mounted in operative relation with'the clutch 12, which is oper- Over the sprocket Wheels 9 and 11 a sprocket chain 14 is pro ated by the lever 13.

vided, whereby-the power of the automobile power plant may be transmittedto the shaft 8, in an obvious manner, for actuating the Upon the'shaft 8 aplurality of arms 15 are mounted, having blades 16 which contact the inner periphery-of the mixing drum 7. The pitch of the blades 16 is such that it 'moves the material in the drum from the front to rear ends of the drum, i. e., in the direction of the arrows 17. Also, upon the shaft 8 are mounted a plurality of propeller blades 18, having a patch which moves the material from the rear end of the drum to the forward end of the drum, i. e.,in. the

direction of the arrows 19. It will be noted that these blades 18 move concentrically with the blades 16, i. e., they move in a region adjacent to the center of the drum, and do not extend to the drum itself. A water tank 20 is mounted upon the drum 7, and from this tank a pipe 21 extends rearwardly. This pipe has a plurality of perforations 22' disposed along its .length, so that water ;may

be delivered throughout the length of the drums 7 I The blades 16 are preferably pivotally mounted at 23 on the arms'15; also on arms 15 a relatively stiff spring 24 is mounted, and is caused to bear upon the outer edge of the blades 16. r

"The mode of operation of a transit con- 'crete mixerembodying my 1nvent1on, is as follows:

At'the bunkers, or other suitable place where the materials are obtained, a batch of gravel, sand and cement is supplied tothe drum, filling the sameapproximately 'to the level indicated by the line 25. The truck is then started towards theqplace of construction work. At the same time, the clutch 12is thrown into operative engagement with the'axle, and'the blades 16 and 18 are caused t'o'rotate, thereby mixingthe material en route.

Or, the material may not be mixed until the truck arrives at the place of loca tion,if it is sodesired. As" the water is admitted to the material, it is mixed thoroughly with the solid parts, all of which are then thoroughly intermixed by means" of the two sets of rotating blades, i. e., by the blades which'move in contact with the periphery of the drum, and the shorter blades which revolve in the region adjacent to the axis of the drum.

Manifestly, the blades 16, disposed in staggered relation along the shaft 8, gradu ally cause the material to move from the forward end to the rear endlof the drum; In so doing, they pick up the material lying adjacent to the periphery of the drum, andcause it to be lifted upwardly in the drum, causing the material to assume the general level indicated by line 25,-Figure 3, while, at the same time, causing it to moverear- Wardly of the drum. At the same time, the blades 18, mounted on the same axis and revolving in the same direction, but havthey location of constructioni's reached, it

is only necessary to open the door 26, and

the material isthen positively forced outof the drum, and the revolving blades 16' overlapping each other in their orbits, must thoroughly scrape and clean the inside of the drum, positively ejecting all of the contents from thedrum so that no delay is incident to cleaning out the drum.

It will be noted that when the shaft 8 first starts to revolve, the material will be dry and a considerable extra effort will be necessary to. mix the. material. However,

as the blade 16 is pivotally mounted at 23,

somewhat above its center, the spring 24 permitsthe blade to tilt backward, as shown in Figure 4; thereby a smaller contacting face is presented by the blade against the material, or, in other words, a smaller quantity of imaterial ismoved by the. blades, so that the power applied to the shaft 8 is more efliciently utilized'in agitating the material as'the material becomes saturated with waposition shown in full line, Figure 4, so that in this positionit is capable of moving the maximum amount of material.

Thus is afforded a transit concrete mixer which is characterized by simplicity of construction and most efficient operation.

Obviously, changes may be made in the forms, shape of mixing drum, dimensions and arrangement of the partsof my invention, without departing from the-principle thereof, the above, setting forth only a preferred form of embodiment,

' I claiin': f V V 15A concrete mixervembodying a fixed mixer drum, a horizontal driven shaft op- -ter, and as it becomes more mobile, the re sista-nce encountered by the blade 16 will be less, and the spring 24 automaticallygradir allycauses the blade'16 to assume the radial eratively mounted Within said drum, a center set of mixing and propelling blades secured to said driven shaft, said central blades disposed to rotate in a region adjacent the axis of the drum, radially disposed arms secured to the driven shaft, outer mixing and propelling blades of opposite pitch to the central blades pivotally secured tosaid arms, the pivot axis being displaced sufficiently from the axis of the blade as to cause the blade to partially revolve When it meets with resistance on its face, resilient means causing the outer blades, to normally present their maximum Working face.

2. A concrete mixer embodying a fixed mixing chamber, a horizontal driven shaft operatively mounted Within said chamber, short mixing and propellingblades secured to the driven shaft and pitched to propel material forward, radially disposed arms secured to the driven shaft, outer mixing and propelling blades pivotally secured to said arms and pitched to move material near the shell, rearward, a pivot for said outer blades the axis of which being only slightly displaced from the'longitudinal axis of the blade and resilient means adapted to normally maintain the blade With its maximum Working surface presented to the material 30 to be mixed.

3. In a horizontal concrete mixer, a mixing and propelling blade mounted on a Working pivot and resiliently held in its operating position, supported on a driving means with its pivot axis slightly displaced from its longitudinal axis, this displacement be ing of sufficient amount that the resistance encountered by the larger portion Will overcome the resistance offered by the smaller portion plus the resistance of the resilient means and cause the blade to revolve thus lessening the total effort required to pass the blade through the mix.

Signed at Seattle, in the county of King 45 and State of Washington, this 21st day of January, 1927.

CLARENCE M. TUCK. 

